Many theorists have hypothesized that young children rely on mental imagery as the predominant mode of internal representation of information in memory. Unfortunately, there is only minimal support for this notion in the literature. Previous research tacts either have been indirect and only tenuously related to this hypothesis, or have been based on a simplistic "picture metaphor" characterization of imagery. The three experiments proposed herein are designed to investigate directly the imagery-reliance claim, and avoid the pitfalls of earlier research. These experiments are based on a proposed information-processing model of how imagery might come into play during question-answering. Reaction-time techniques are used to study the frequency with which children and adults necessarily access imagery in order to answer questions about the relative sizes of objects. The experiments assess the time required to decide which of two objects is larger in conditions where pictures of the objects are presented or where only the names are given (requiring memory comparisons).